Advances in leprosy immunology and the field application: A gap to bridge

Abstract

Advances concerning the hosts' immune response to Mycobacterium leprae infection have focused on elucidating the immune pathomechanisms involved, with the hope that predictive diagnostic and prognostic parameters (biomarkers) for field use would emerge; however, improvements in our understanding of the immunologic responses to this complex disease have, to date, somewhat failed to provide the effective and robust methods for improving its predictive diagnosis in the field situation, particularly in those patients suffering from paucibacillary disease. In this contribution we have attempted to review some of the advances both in the immunology and immunopathology of leprosy, and also highlight the limited clusters of immune parameters that are now available. Most importantly, we point out the limitations that still prevail in the provision of effective biomarkers in the field situation for either: (1) the diagnosis of indeterminate disease, (2) predictive diagnosis of individuals developing reactional states, (3) monitoring efficacy of treatment, or (4) monitoring treatment of reactional states.

Endoplasmic Reticulum Stress Markers and Their Possible Implications in Leprosy’s Pathogenesis

“…The interaction between M. leprae and the host is complex, and the disease presents a chronic evolution that affects mainly the skin and peripheral nerves. Its clinical manifestations vary and are associated with diverse host-dependent factors such as the pattern of innate and adaptive immune response, as well as genetic and immunogenetic factors [1–3]. Immune response patterns to M. leprae have been shown to involve components of innate immunity, such as dendritic cells, macrophages (both M1 and M2 subtypes), and natural killer cells, as well as diverse types of lymphocytes, such as T helper cells (Th1, Th2, Th17, Th9, Th22, and Th25) [4–8].…”

The involvement of endothelial mediators in leprosy

“…T1R usually occurs in preexisting lesions ( Scollard et al 2006) . T2R develops in lepromatous leprosy (LL) and borderline lepromatous (BL), in which is observed high bacterial load and ill-defined antigen specific T cells functions (de Souza et al 2016) . T2R is described as abruptly induced recurrent episodes of immune complex-mediated reactions, where local signs are accompanied by systemic involvement ( Stefani et al 2009 , Cortela et al 2015) .…”

Position statement: LEPROSY: Diagnosis, treatment and follow‐up

“…However, this test may be positive in contacts and negative in PB leprosy. It helps to classify leprosy into PB and MB and it can be used to follow the effect of treatment in MB patients and to detect relapses . The value of the recently introduced synthetic ‘LID‐1’ seems to add little.…”